Object Initialization

The process of specifying an initial value for an object is called initialization.

1. Types of initialization:

• int a default initialization: no initializer

• Traditional forms:

  • int a = 5 copy initialization
    • inherited from C, used to not be efficient for complex objects
  • int a (5) direct initialization
    • introduced to be more efficient for complex objects

• Modern forms: (RECOMMENDED)

  • int a { 5 } direct list initialization
    • Prior to C++11 there were a lot of special requirements for different initializations, list initialization was made to work in all situations and behave consistently;
    • It's called list initialization because it provides a way to initialize objects with a list of values rather than a single one;
    • Disallows narrowing conversions, gives a warning or an error.
  • int a {} value initialization (or zero initialization)
    • initializes the variables to zero or whatever is closest to it (zero initialization). For objects, it could initialize to predefined values (value initialization).
  • and some others... #stub

Sometimes we have a lot of reused variables that sometimes don't get used. in such cases we can add [[maybe_unused]].

1.2. Performance

When initializing a shit ton of variables, sometimes it can be useful to use default initialization (that leaves an undefined variable).